The term "cable" is used below to designate a set of electrical and/or optical conductors contained in an outer covering. The wire armoring is constituted by one or more layers of wires generally made of metal and wound helically around the cable. The cables to which the invention applies are thus wire-armored cables.
This type of cable covered in wire armoring is widely used when the cable needs to withstand large traction forces without being damaged, and needs to withstand making contact with objects which are sharp or abrasive. A typical example is constituted by under-sea cables laid in waters of medium depth, in particular close to the shore, which cables must be capable of withstanding forces from anchors and from fishing tackle, and which must also be able to withstand the traction exerted by their own weight between a cable-laying ship and the sea bottom.
In general, the splice between two cables provided with armoring is frequently made on board a cable-laying ship, using the following technique which is well known to the person skilled in the art. After reconstituting electrical and/or optical continuity of the electrical and/or optical conductors contained in the core of the cables, and after reconstituting the outer protective covering by taping or by molding on thermoplastic material, or by soldering on a lead sleeve, the armoring wires from each cable end on either side of the splice are rewound by hand around the splice so that the wires of one end are interposed between the wires from the other end in the vicinity of the splice and overlie one another over a certain distance on either side of the splice, with the assembly being held together by one or more auxiliary wires wound with contiguous turns in each of the two zones containing armoring wires of one cable end overlapping the wires of the other cable end.
Reconstituting the armoring around a splice using this method takes a long time, is difficult to do, and does not guarantee that the zone containing the splice in the connected cable is capable of withstanding as large a traction force as the cable can withstand outside the splice zone. When a spliced cable is subjected to traction, the wires of one of the ends may slide between or over the wires of the other end.
In order to solve this problem, French patent document FR-A No. 2 537 357 in the same of LES CABLES DE LYON proposes connecting each wire on one of the ends to a corresponding wire on the other end by means of a sleeve tapped at each end with oppositely-handed threads. This prevents the wires on one end sliding relative to those on the other, but the traction strength at the sleeves nevertheless remains weaker than in uninterrupted cable since the threading operation reduces the cross-section of each wire.
The object of the present invention is to obtain mechanical performance in the splice zone of a spliced cable which is no worse than the mechanical performance away from the slice, and which corresponds to the composition and the dimensions of the, or each, layer of wire armoring provided on the cable. The same splice can be used for interconnecting the armoring of two cables having different structures of armoring, e.g. different numbers of layers, or different dimensions, e.g. in layer diameter, or in number of wires, or in wire diameter.